INVERSE DYNAMICS OF SPATIAL OPEN-CHAIN FLEXIBLE MANIPULATORS WITH LUMPED AND DISTRIBUTED ACTUATORS

This article addresses the problem of inverse dynamics for three-dimen sional flexible manipulators with both lumped and distributed actuator s. A recursive procedure is presented for computing the lumped inverse dynamic torques and the distributed piezoelectric actuator inputs for simultaneously tracking a prescribed end-point trajectory and reducin g induced vibrations in the manipulator. The procedure sequentially so lves for the non-causal inverse dynamic torques and piezoelectric volt ages applied to each link in the manipulator, starting from the last e lement in the chain and proceeding to the base element. The method all ows trajectory tracking wherein controllability of the structural vibr ations is assured in all possible configurations through the use of on ly one motor at each intermediate joint and three motors at the ground . Numerical simulation shows that the elastic vibrations can be reduce d significantly through the use of distributed actuators while at the same time satisfying the trajectory tracking requirement through the u se of inverse dynamics. (C) 1994 John Wiley & Sons, Inc.